1. Field of the Invention
The present invention relates to an image capturing apparatus having an optical viewfinder function and an electronic viewfinder function.
2. Description of the Related Art
In general, users of single-lens reflex digital cameras use an optical viewfinder in order to monitor an object of shooting. However, some single-lens reflex digital cameras have an electronic viewfinder function of displaying an object on a monitor in a moving manner (refer to, for example, Japanese Unexamined Patent Application Publication No. 2006-251065).
Japanese Unexamined Patent Application Publication No. 2006-251065 describes the following technology. Autofocus (AF) control is performed using a contrast detection method while a user is composing a shot using an electronic viewfinder with a mirror staying in the up position (in an electronic viewfinder mode), and AF control is performed using a phase difference detection method while a user is composing a shot using an optical viewfinder with the mirror staying in the down position (in an optical viewfinder mode).
In general, in AF control using a phase difference detection method with the mirror staying in the down position, a phase difference AF module including an exposure metering sensor, such as a line sensor, is used. However, theoretically, it is difficult for a phase difference AF module to support a large number of AF areas. In contrast, AF control using a contrast detection method can set a large number of AF areas in an imaging surface.